Engine is intermittently flooding on startup

accordvtec77

accordvtec77

Joined
Aug 29, 2019
Messages
26
Age
47
Location
American Canyon, CA
Sorry if this was the wrong sub-forum to post this...my 06 with 49k miles has done this twice in two weeks now. Yesterday afternoon as I was leaving work, I went to fire up the bike. It bogged down and died almost immediately. Started it a second time...same result. Third time I gave it quite a bit of throttle to keep the engine running. I can definitely tell that it was running VERY rich on startup because of the smell while I had the throttle open, and the engine was running in a manner that indicated that it was flooded with gasoline. After about 10 seconds of high revving, it cleared itself out and ran normally again. The FI light never came on. She was fine all the way home (36 miles), and started up normally this morning. Now this is the second time this had happened. It happened last week, only then the FI light DID come on shortly after I left work. I had/have no idea how to pull codes from a motorcycle, but the FI light didn't come back on after shutting the bike off, and restarting it.

If this was an automobile...I'd be looking at coolant temp sensor, or MAF readings. But because I know extremely little about how motorcycles work...I'm at a loss as to what the problem may be. I replaced the spark plugs about 1.5 months ago, and I got them from a Honda Powersports dealer (not aftermarket plugs). I also made sure the plug wires were secured, and the plugs were properly gapped before installation. Has anyone else ran into this issue? Thanks in advance.
 
Usually, when a fuel injected engine floods it's due to a stuck or leaky injector. When it does this it will relieve the pressure in the fuel system meaning it will have to re-pressurize to start. The times that it has done this, do you recall if it took longer than usual to prime the fuel system before starting? Did it crank longer than usual?
Read up on how to retrieve the codes. That could be very important if it does it again and gives you a code.
 
I'd check some things in this order (level of difficulty)... add a can of Sea Foam or Techron to the tank. Check and clean the air filter. Clean out the 5-way T. Do a search here, plenty of info on it.
 
I'm with Whooshka on this one
If it is the fuel injectors gunking up keep seafoam and Techron in the tank. and off of Igofar advice I even add MMO every other tank if I can.
 
Bmacleod said:
Usually, when a fuel injected engine floods it's due to a stuck or leaky injector. When it does this it will relieve the pressure in the fuel system meaning it will have to re-pressurize to start. The times that it has done this, do you recall if it took longer than usual to prime the fuel system before starting? Did it crank longer than usual?
Read up on how to retrieve the codes. That could be very important if it does it again and gives you a code.
Click to expand...

Crank time was normal both times it occurred. Now I've never ran cheap fuel in that bike, at least as long as I've owned it. And I've always run 91 Octane. All the same, I've purchased some bottles of Sea Foam fuel additive and will be using it regularly. Regarding any stored DTC's though...I had searched last week on how to retrieve them, should the FI light come back on. But I'm getting "conflicted" answers. I've read that a certain connector has to be jumped, and count the flashes...others have suggested that all I need to do is pull the bike over, engine running in neutral, and put the sidestand down. So if you could clarify, I'd be very grateful.
 
accordvtec77 said:
I've read that a certain connector has to be jumped, and count the flashes...others have suggested that all I need to do is pull the bike over, engine running in neutral, and put the sidestand down. So if you could clarify, I'd be very grateful.
Click to expand...

Both methods will achieve the desired result.
 
Even if the FI light has turned off there should still be a code in the ECM's memory for some amount of time or key cycles. Try turning the key on without starting the engine and then lower the side stand. If there's a code stored it should now start blinking out. The alternative way is to jump the red connector (forget between which two wires) under the passenger seat.

I'm skeptical the bike is actually flooding but I had the same behavior you describe accompanied by a code 2, i.e. two rapid blinks. Like yours, it would kind of come and go. Two rapid blinks indicates a MAP sensor fault, but in my experience the MAP sensor itself is usually OK, instead the 5-way vacuum "T" or one of the vacuum lines connected to it has become clogged isolating the MAP sensor from intake vacuum, thus setting the code.
 
wjbertrand said:
Even if the FI light has turned off there should still be a code in the ECM's memory for some amount of time or key cycles. Try turning the key on without starting the engine and then lower the side stand. If there's a code stored it should now start blinking out. The alternative way is to jump the red connector (forget between which two wires) under the passenger seat.

I'm skeptical the bike is actually flooding but I had the same behavior you describe accompanied by a code 2, i.e. two rapid blinks. Like yours, it would kind of come and go. Two rapid blinks indicates a MAP sensor fault, but in my experience the MAP sensor itself is usually OK, instead the 5-way vacuum "T" or one of the vacuum lines connected to it has become clogged isolating the MAP sensor from intake vacuum, thus setting the code.
Click to expand...

I've definitely taken the vacuum T into consideration, along with everyone else's suggestions. I purchased some Sea Foam additive...gonna get my hands on some MMO tomorrow morning. Since I'm not sure WHEN the air filter itself was last replaced, I ordered a K&N from Amazon which should arrive in a few days. So I figured probably next weekend, when I replace the air filter...I'll go a bit further and take care of that vacuum T connector.

EDIT: She's on the center stand right now. I put the side stand UP, turned the key on like you suggested, and brought the side stand back down. The FI light didn't flash or do anything. Since it's been well over a week since that light came on...the code may have cleared itself out by now.
 
Like @wjbertrand , I am skeptical that it is actually flooding. Once, last year, I had a very similar situation. I started the bike cold and it ran like absolute crap and it was stumbling and misfiring like it was flooded. I shut it off, wondering what the heck was going on and I restarted it and it was fine and it's never done it since. I had forgotten all about it until I read this thread.
 
Whooshka said:
Any update?
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No update as yet...it hasn't done it since I first posted about it. But I did have a conversation with Igofar regarding this issue. This weekend I WILL be digging into that 5-way vacuum assembly. I ordered a set of those JIS screwdrivers so that I'd have the proper tools on hand before I started poking around, taking things apart.
 
So here's my update...I removed the air filter box assembly to get at the 5-way vacuum port. The hoses themselves seemed pretty brittle, and I didn't want to risk breaking them OR the tee itself. SOOOOOO...I've ordered a new vacuum tee, and I'll order some new hose material and just replace EVERYTHING.
 
accordvtec77 said:
So here's my update...I removed the air filter box assembly to get at the 5-way vacuum port. The hoses themselves seemed pretty brittle, and I didn't want to risk breaking them OR the tee itself. SOOOOOO...I've ordered a new vacuum tee, and I'll order some new hose material and just replace EVERYTHING.
Click to expand...
If you pull the lines they act like a Chinese finger trap, to remove the lines, pull them off the brass tb nipples and remove the map sensor switch/tee/lines as one unit.
Then PUSH the lines off the tee after putting a drop of penetrating oil on the joint.
 
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